Multiple bssid procedure with tim encoding

ABSTRACT

Certain aspects of the present disclosure provide methods and apparatus for s wireless communications, comprising a processing system configured to generate a frame with an information element (IE) having a partial virtual bitmap field that indicates zero or more basic service sets (BSSs) that have buffered group-cast traffic, wherein the partial virtual bitmap field comprises at least one encoded subfield that identities at least one individual BSS having buffered group-cast traffic using one or more bits of an identifier of the individual BSS, and an interface for outputting the frame containing the IE for transmission.

CLAIM OF PRIORITY UNDER 35 U.S.C. §119

The present Application for Patent claims benefit of U.S. ProvisionalPatent Application Ser. No. 61/986,055, filed Apr. 29, 2014 and assignedto the assignee hereof and hereby expressly incorporated by referenceherein.

BACKGROUND

1. Field of the Invention

Certain aspects of the present disclosure generally relate to wirelesscommunications and, more particularly, to multiple BSSID with TIMencoding.

2. Relevant Background

Wireless communication networks are widely deployed to provide variouscommunication services such as voice, video, packet data, messaging,broadcast, etc. These wireless networks may be multiple-access networkscapable of supporting multiple users by sharing the available networkresources. Examples of such multiple-access networks include CodeDivision Multiple Access (CDMA) networks, Time Division Multiple Access(TDMA) networks, Frequency Division Multiple Access (FDMA) networks,Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA)networks.

In order to address the desire for greater coverage and increasedcommunication range, various schemes are being developed. One suchscheme is the sub-1-GHz frequency range (e.g., operating in the 902-928MHz range in the United States) being developed by the Institute ofElectrical and Electronics Engineers (IEEE) 802.11ah task force. Thisdevelopment is driven by the desire to utilize a frequency range thathas greater wireless range than other IEEE 802.11 groups and has lowerobstruction losses.

SUMMARY

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus typically includes a processingsystem configured to generate a frame with an information element (IE)having a partial virtual bitmap field that indicates one or more basicservice sets (BSSs) that have buffered group-cast traffic, wherein thepartial virtual bitmap field comprises at least one encoded subfieldthat identifies at least one individual BSS having buffered group-casttraffic using one or more bits of an association identification orassigned identification (AID) of the individual BSS and an interface foroutputting a frame containing the IE for transmission.

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus typically includes an interfacefor receiving a frame containing an information element (IE) and aprocessing system configured to determine the presence of bufferedgroup-cast traffic for the apparatus based on a partial virtual bitmapfield in the IE, that indicates one or more basic service sets (BSSs)that have buffered group-cast traffic, wherein the bitmap fieldcomprises at least one encoded subfield that identifies at least oneindividual BSS having buffered group-cast traffic using one or more bitsof an association identification or assigned identification (AID) of theindividual BSS.

Certain aspects of the present disclosure provide a method for wirelesscommunications by an apparatus. The method typically includesgenerating, at an apparatus, a frame with an information element (IE)having a partial virtual bitmap field that indicates zero or more basicservice sets (BSSs) that have buffered group-cast traffic, wherein thepartial virtual bitmap field comprises at least one encoded subfieldthat identifies at least one individual BSS having buffered group-casttraffic using one or more bits of an identifier of the individual BSS,and outputting the frame containing the IE for transmission.

Certain aspects of the present disclosure provide a method for wirelesscommunications by an apparatus. The method typically includes receiving,at an apparatus, a frame containing an information element (IE), whereinthe IE comprises a partial virtual bitmap field that indicates zero ormore basic service sets (BSSs) that have buffered group-cast traffic andat least one encoded subfield that identifies at least one individualBSS having buffered group-cast traffic using one or more bits of anidentifier of the individual BSS, and determining the presence ofbuffered group-cast traffic for the apparatus based on the partialvirtual bitmap and to decide whether or not to change at least one powerstate to receive the buffered group-cast traffic, based on thedetermination.

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus typically includes means forgenerating a frame with an information element (IE) having a partialvirtual bitmap field that indicates zero or more basic service sets(BSSs) that have buffered group-cast traffic, wherein the partialvirtual bitmap field comprises at least one encoded subfield thatidentifies at least one individual BSS having buffered group-casttraffic using one or more bits of an identifier of the individual BSS,and means for outputting the frame containing the IE for transmission.

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus typically includes means forreceiving a frame containing an information element (IE) wherein the IEcomprises a partial virtual bitmap field that indicates zero or morebasic service sets (BSSs) that have buffered group-cast traffic and atleast one encoded subfield that identifies at least one individual BSShaving buffered group-cast traffic using one or more bits of anidentifier of the individual BSS and means for determining the presenceof buffered group-cast traffic for the apparatus based on the partialvirtual bitmap and to decide whether or not to change at least one powerstate to receive the buffered group-cast traffic, based on thedetermination.

Certain aspects of the present disclosure provide a computer programproduct for wireless communications. The computer program producttypically comprises a computer-readable medium having instructions forgenerating a frame with an information clement (IE) having a partialvirtual bitmap field that indicates zero or more basic service sets(BSSs) that have buffered group-cast traffic, wherein the partialvirtual bitmap field comprises at least one encoded subfield thatidentifies at least one individual BSS having buffered group-casttraffic using one or more bits of an identifier of the individual BSS,and outputting the frame containing the IE for transmission.

Certain aspects of the present disclosure provide a computer programproduct for wireless communications. The computer program producttypically comprises a computer-readable medium having instructions forreceiving, at an apparatus, a frame containing an information element(IE), wherein the IE comprises a partial virtual bitmap field thatindicates zero or more basic service sets (BSSs) that have bufferedgroup-cast traffic and at least one encoded subfield that identifies atleast one individual BSS having buffered group-cast traffic using one ormore bits of an identifier of the individual BSS and determining thepresence of buffered group-cast traffic for the apparatus based on thepartial virtual bitmap and to decide whether or not to change at leastone power state to receive the buffered group-cast traffic, based on thedetermination.

Certain aspects of the present disclosure provide an access point. Theaccess point typically includes at least one antenna, a processingsystem configured to generate a frame with an information element (IE)having a partial virtual bitmap field that indicates zero or more basicservice sets (BSSs) that have buffered group-cast traffic, wherein thepartial virtual bitmap field comprises at least one encoded subfieldthat identifies at least one individual BSS having buffered group-casttraffic using one or more bits of an identifier of the individual BSS,and a transmitter configured to transmit, via the at least one antenna,the frame containing the IE for transmission.

Certain aspects of the present disclosure provide an access point. Theaccess point typically includes at least one antenna, a receiverconfigured to receive, via the at least one antenna, a frame containingan information element (IE), wherein the IE comprises a partial virtualbitmap field that indicates zero or more basic service sets (BSSs) thathave buffered group-cast traffic and at least one encoded subfield thatidentifies at least one individual BSS having buffered group-casttraffic using one or more bits of an identifier of the individual BSS,and a processing system configured to determine the presence of bufferedgroup-cast traffic for the apparatus based on the partial virtualbit/nap and to decide whether or not to change at least one power stateto receive the buffered group-cast traffic, based on the determination.

Certain aspects also provide various methods, apparatuses, and computerprogram products capable of performing operations corresponding to thosedescribed above.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to aspects, some ofwhich are illustrated in the appended drawings. It is to be noted,however, that the appended drawings illustrate only certain typicalaspects of this disclosure and are therefore not to be consideredlimiting of its scope, for the description may admit to other equallyeffective aspects.

FIG. 1 illustrates a diagram of an example wireless communicationsnetwork, in accordance with certain aspects of the present disclosure.

FIG. 2 illustrates a block diagram of an example access point and userterminals, in accordance with certain aspects of the present disclosure.

FIG. 3 illustrates a block diagram of an example wireless device, inaccordance with certain aspects of the present disclosure.

FIG. 4 illustrates an example tree structure of a relay system, inaccordance with certain aspects of the present disclosure.

FIG. 5 illustrates an example hierarchical structure of a trafficindication map (TIM), in accordance with certain aspects of the presentdisclosure.

FIGS. 6A-6D illustrates example structures of a partial virtual bitmapfor a block encoding mode, in accordance with certain aspects of thepresent disclosure.

FIG. 7 illustrates an example structure of a partial virtual bitmap fora single association ID (AID) mode, in accordance with certain aspectsof the present disclosure.

FIG. 8 illustrates a block diagram of example operations for wirelesscommunications, in accordance with certain aspects of the presentdisclosure.

FIG. 8A illustrates example means capable of performing the operationsshown in FIG. 8.

FIG. 9 illustrates a block diagram of example operations for wirelesscommunications, in accordance with certain aspects of the presentdisclosure.

FIG. 9A illustrates example means capable of performing the operationsshown FIG. 9.

FIG. 10 illustrates an example structure for an encoded block of apartial virtual bitmap, in accordance with aspects of the presentdisclosure.

DETAILED DESCRIPTION

Aspects of the present disclosure provide enhancements to mechanismsinvolving certain selective transmission mechanisms, such as partialvirtual bitmaps (PVB) and multiple basic service set IDs (BSSIDs). Byproviding an indication of multiple BSSID in a partial virtual bitmap(PVB) of a Traffic Indication Map (TIM) Information Element (IE),support for multiple BSS while using an association identification (AID)may be provided.

Various aspects of the disclosure are described more fully hereinafterwith reference to the accompanying drawings. This disclosure may,however, be embodied in many different forms and should not be construedas limited to any specific structure or function presented throughoutthis disclosure. Rather, these aspects are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art. Based on theteachings herein one skilled in the art should appreciate that the scopeof the disclosure is intended to cover any aspect of the disclosuredisclosed herein, whether implemented independently of or combined withany other aspect of the disclosure. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, the scope of the disclosure is intendedto cover such an apparatus or method which is practiced using otherstructure, functionality, or structure and functionality in addition toor other than the various aspects of the disclosure set forth herein. Itshould be understood that any aspect of the disclosure disclosed hereinmay be embodied by one or more elements of a claim.

Although particular aspects are described herein, many variations andpermutations of these aspects fall within the scope of the disclosure.Although some benefits and advantages of the preferred aspects arementioned, the scope of the disclosure is not intended to be limited toparticular benefits, uses, or objectives. Rather, aspects of thedisclosure are intended to be broadly applicable to different wirelesstechnologies, system configurations, networks, and transmissionprotocols, some of which are illustrated by way of example in thefigures and in the following description of the preferred aspects. Thedetailed description and drawings are merely illustrative of thedisclosure rather than limiting, the scope of the disclosure beingdefined by the appended claims and equivalents thereof.

An Example Wireless Communication System

The techniques described herein may be used for various broadbandwireless communication systems, including communication systems that arebased on an orthogonal multiplexing scheme. Examples of suchcommunication systems include Spatial Division Multiple Access (SDMA),Time Division Multiple Access (TDMA), Orthogonal Frequency DivisionMultiple Access (OFDMA) systems, Single-Carrier Frequency DivisionMultiple Access (SC-FDMA) systems, and so forth. An SDMA system mayutilize sufficiently different directions to simultaneously transmitdata belonging to multiple user terminals. A TDMA system may allowmultiple user terminals to share the same frequency channel by dividingthe transmission signal into different time slots, each time slot beingassigned to different user terminal An OFDMA system utilizes orthogonalfrequency division multiplexing (OFDM), which is a modulation techniquethat partitions the overall system bandwidth into multiple orthogonalsub-carriers. These sub-carriers may also be called tones, bins, etc.With OFDM, each sub-carrier may be independently modulated with data. AnSC-FDMA system may utilize interleaved FDMA (IFDMA) to transmit onsub-carriers that are distributed across the system bandwidth, localizedFDMA (LFDMA) to transmit on a block of adjacent sub-carriers, orenhanced FDMA (EFDMA) to transmit on multiple blocks of adjacentsub-carriers. In general, modulation symbols are sent in the frequencydomain with OFDM and in the time domain with SC-FDMA.

The teachings herein may be incorporated into (e.g., implemented withinor performed by) a variety of wired or wireless apparatuses (e.g., nodesor devices). In some aspects, a wireless node implemented in accordancewith the teachings herein may comprise an access point or an accessterminal.

An access point (“AP”) may comprise, be implemented as, or known as aNode B, Radio Network Controller (“RNC”), evolved Node B (eNB), BaseStation Controller (“BSC”), Base Transceiver Station (“BTS”), BaseStation (“BS”), Transceiver Function (“TF”), Radio Router, RadioTransceiver, Basic Service Set (“BSS”), Extended Service Set (“ESS”),Radio Base Station (“RBS”), or some other terminology.

An access terminal (“AT”) may comprise, be implemented as, or known as asubscriber station, a subscriber unit, a mobile station (MS), a remotestation, a remote terminal, a user terminal (UT), a user agent, a userdevice, user equipment (UE), a user station, or some other terminology.In some implementations, an access terminal may comprise a cellulartelephone, a cordless telephone, a Session Initiation Protocol (“SIP”)phone, a wireless local loop (“WLL”) station, a personal digitalassistant (“PDA”), a handheld device having wireless connectioncapability, a Station (“STA”), or some other suitable processing deviceconnected to a wireless modem. Accordingly, one or more aspects taughtherein may be incorporated into a phone (e.g., a cellular phone or smartphone), a computer (e.g., a laptop), a tablet, a portable communicationdevice, a portable computing device (e.g., a personal data assistant),an entertainment device (e.g., a music or video device, or a satelliteradio), a global positioning system (GPS) device, or any other suitabledevice that is configured to communicate via a wireless or wired medium.In some aspects, the node is a wireless node. Such wireless node mayprovide, for example, connectivity for or to a network (e.g., a widearea network such as the Internet or a cellular network) via a wired orwireless communication link.

FIG. 1 illustrates a multiple-access multiple-input multiple-output(MIMO) system 100 with access points and user terminals. For simplicity,only one access point 110 is shown in FIG. 1. An access point isgenerally a fixed station that communicates with the user terminals andmay also be referred to as a base station or some other terminology. Auser terminal may be fixed or mobile and may also be referred to as amobile station, a wireless device, or some other terminology. Accesspoint 110 may communicate with one or more user terminals 120 at anygiven moment on the downlink and uplink. The downlink (i.e., forwardlink) is the communication link from the access point to the userterminals, and the uplink (i.e., reverse link) is the communication linkfrom the user terminals to the access point. A user terminal may alsocommunicate peer-to-peer with another user terminal A system controller130 couples to and provides coordination and control for the accesspoints.

While portions of the following disclosure will describe user terminals120 capable of communicating via Spatial Division Multiple Access(SDMA), for certain aspects, the user terminals 120 may also includesome user terminals that do not support SDMA. Thus, for such aspects, anAP 110 may be configured to communicate with both SDMA and non-SDMA userterminals. This approach may conveniently allow older versions of userterminals (“legacy” stations) to remain deployed in an enterprise,extending their useful lifetime, while allowing newer SDMA userterminals to be introduced as deemed appropriate.

The system 100 employs multiple transmit and multiple receive antennasfor data transmission on the downlink and uplink. The access point 110is equipped with N_(ap) antennas and represents the multiple-input (MI)for downlink transmissions and the multiple-output (MO) for uplinktransmissions. A set of K selected user terminals 120 collectivelyrepresents the multiple-output for downlink transmissions and themultiple-input for uplink transmissions. For pure SDMA, it is desired tohave N_(ap)≧K≧1 if the data symbol streams for the K user terminals arenot multiplexed in code, frequency or time by some means. K may begreater than N_(ap) if the data symbol streams can be multiplexed usingTDMA technique, different code channels with CDMA, disjoint, sets ofsubbands with OFDM, and so on. Each selected user terminal transmitsuser-specific data to and/or receives user-specific data from the accesspoint. In general, each selected user terminal may be equipped with oneor multiple antennas (i.e., N_(ut)≧1). The K selected user terminals canhave the same or different number of antennas.

The SDMA system may be a time division duplex (TDD) system or afrequency division duplex (FDD) system. For a TDD system, the downlinkand uplink share the same frequency band. For an FDD system, thedownlink and uplink use different frequency bands. MIMO system 100 mayalso utilize a single carrier or multiple carriers for transmission.Each user terminal may be equipped with a single antenna (e.g., in orderto keep costs down) or multiple antennas (e.g., where the additionalcost can be supported). The system 100 may also be a TDMA system if theuser terminals 120 share the same frequency channel by dividingtransmission/reception into different time slots, each time slot beingassigned to different user terminal 120.

FIG. 2 illustrates a block diagram of access point 110 and two userterminals 120 m and 120 x in MIMO system 100. The access point 110 isequipped with N_(l) antennas 224 a through 224 t. User terminal 120 m isequipped with N_(ut,m) antennas 252 ma through 252 mu, and user terminal120 x is equipped with N_(ut,x) antennas 252 xa through 252 xu. Theaccess point 110 is a transmitting entity for the downlink and areceiving entity for the uplink. Each user terminal 120 is atransmitting entity for the uplink and a receiving entity for thedownlink. As used herein, a “transmitting entity” is an independentlyoperated apparatus or device capable of transmitting data via a wirelesschannel, and a “receiving entity” is an independently operated apparatusor device capable of receiving data via a wireless channel. In thefollowing description, the subscript “dn” denotes the downlink, thesubscript “up” denotes the uplink, N_(up) user terminals are selectedfor simultaneous transmission on the uplink, N_(dn) user terminals areselected for simultaneous transmission on the downlink, N_(up) may ormay not be equal to N_(dn), and N_(up) and N_(dn) may be static valuesor can change for each scheduling interval. The beam-steering or someother spatial processing technique may be used at the access point anduser terminal.

On the uplink, at each user terminal 120 selected for uplinktransmission, a transmit (TX) data processor 288 receives traffic datafrom a data source 286 and control data from a controller 280. TX dataprocessor 288 processes (e.g., encodes, interleaves, and modulates) thetraffic data for the user terminal based on the coding and modulationschemes associated with the rate selected for the user terminal andprovides a data symbol stream. A TX spatial processor 290 performsspatial processing on the data symbol stream and provides N_(ut,m)transmit symbol streams for the N_(ut,m) antennas. Each transmitter unit(TMTR) 254 receives and processes (e.g., converts to analog, amplifies,filters, and frequency upconverts) a respective transmit symbol streamto generate an uplink signal. N_(ut,m) transmitter units 254 provideN_(ut,m) uplink signals for transmission from N_(ut,m) antennas 252 tothe access point.

N_(up) user terminals may be scheduled for simultaneous transmission onthe uplink. Each of these user terminals performs spatial processing onits data symbol stream and transmits its set of transmit symbol streamson the uplink to the access point.

At access point 110, N_(ap) antennas 224 a through 224 ap receive theuplink signals from all N_(ap) user terminals transmitting on theuplink. Each antenna 224 provides a received signal to a respectivereceiver unit (RCVR) 222. Each receiver unit 222 performs processingcomplementary to that performed by transmitter unit 254 and provides areceived symbol stream. An RX spatial processor 240 performs receiverspatial processing on the N_(ap) received symbol streams from N_(ap)receiver units 222 and provides N_(ap) recovered uplink data symbolstreams. The receiver spatial processing is performed in accordance withthe channel correlation matrix inversion (CCMI), minimum mean squareerror (MSSE), soft interference cancellation (SIC), or some othertechnique. Each recovered uplink data symbol stream is an estimate of adata symbol stream transmitted by a respective user terminal. An RX dataprocessor 242 processes (e.g., demodulates, deinterleaves, and decodes)each recovered uplink data symbol stream in accordance with the rateused for that stream to obtain decoded data. The decoded data for eachuser terminal may be provided to a data sink 244 for storage and/or acontroller 230 for further processing.

On the downlink, at access point 110, a TX data processor 210 receivestraffic data from a data source 208 for N_(dn) user terminals scheduledfor downlink transmission, control data from a controller 230, andpossibly other data from a scheduler 234. The various types of data maybe sent on different transport channels. TX data processor 210 processes(e.g., encodes, interleaves, and modulates) the traffic data for eachuser terminal based on the rate selected for that user terminal. TX dataprocessor 210 provides N_(dn) downlink data symbol streams for theN_(dn) user terminals. A TX spatial processor 220 performs spatialprocessing (such as a precoding or beamforming, as described in thepresent disclosure) on the N_(dn) downlink data symbol streams, andprovides N_(ap) transmit symbol streams for the N_(ap) antennas. Eachtransmitter unit 222 receives and processes a respective transmit symbolstream to generate a downlink signal. N_(ap) transmitter units 222providing N_(ap) downlink signals for transmission from N_(ap) antennas224 to the user terminals.

At each user terminal 120, N_(ut,m) antennas 252 receive the N_(ap)downlink signals from access point 110. Each receiver unit 254 processesa received signal from an associated antenna 252 and provides a receivedsymbol stream. An RX spatial processor 260 performs receiver spatialprocessing on N_(ut,m) received symbol streams from N_(ut,m) receiverunits 254 and provides a recovered downlink data symbol stream for theuser terminal. The receiver spatial processing is performed inaccordance with the CCMI, MMSE or some other technique. An RX dataprocessor 270 processes (e.g., demodulates, deinterleaves and decodes)the recovered downlink data symbol stream to obtain decoded data for theuser terminal.

At each user terminal 120, a channel estimator 278 estimates thedownlink channel response and provides downlink channel estimates, whichmay include channel gain estimates. SNR estimates, noise variance and soon. Similarly, a channel estimator 228 estimates the uplink channelresponse and provides uplink channel estimates. Controller 280 for eachuser terminal typically derives the spatial filter matrix for the userterminal based on the downlink channel response matrix H_(dn,m) for thatuser terminal. Controller 230 derives the spatial filter matrix for theaccess point based on the effective uplink channel response matrixH_(up,eff). Controller 280 for each user terminal may send feedbackinformation (e.g., the downlink and/or uplink eigenvectors, eigenvalues,SNR estimates, and so on) to the access point. Controllers 230 and 280also control the operation of various processing units at access point110 and user terminal 120, respectively.

FIG. 3 illustrates various components that may be utilized in a wirelessdevice 302 that may be employed within the MIMO system 100. The wirelessdevice 302 is an example of a device that may be configured to implementthe various methods described herein. The wireless device 302 may be anaccess point 110 or a user terminal 120.

The wireless device 302 may include a processor 304 which controlsoperation of the wireless device 302. The processor 304 may also bereferred to as a central processing unit (CPU). Memory 306, which mayinclude both read-only memory (ROM) and random access memory (RAM),provides instructions and data to the processor 304. A portion of thememory 306 may also include non-volatile random access memory (NVRAM).The processor 304 typically performs logical and arithmetic operationsbased on program instructions stored within the memory 306. Theinstructions in the memory 306 may be executable to implement themethods described herein.

The wireless device 302 may also include a housing 308 that may includea transmitter 310 and a receiver 312 to allow transmission and receptionof data between the wireless device 302 and a remote location. Thetransmitter 310 and receiver 312 may be combined into a transceiver 314.A single or a plurality of transmit antennas 316 may be attached to thehousing 308 and electrically coupled to the transceiver 314. Thewireless device 302 may also include (not shown) multiple transmitters,multiple receivers, and multiple transceivers.

The wireless device 302 may also include a signal detector 318 that maybe used in an effort to detect and quantify the level of signalsreceived by the transceiver 314. The signal detector 318 may detect suchsignals as total enemy, energy per subcarrier per symbol, power spectraldensity and other signals. The wireless device 302 may also include adigital signal processor (DSP) 320 for use in processing signals.

The various components of the wireless device 302 may be coupledtogether by a bus system 322, which may include a power bus, a controlsignal bus, and a status signal bus in addition to a data bus.

Example Target Wait Time Flow ID Signaling

In a relay system utilizing low power devices as relays, it may bedesirable to allow relays to enter a low power mode (e.g., sleep withone or more components powered down) whenever possible to reduce powerconsumption. Further, to keep costs down, it may be desirable to userelays with only limited memory. Thus, a relay may be able to bufferonly a small amount of data, and may need to forward the data beforebeing able to receive more.

In a multi-hop relay system, such as that shown in FIG. 4, this maypresent some challenges on how to conserve power-and still ensuredevices are awake at appropriate times to relay data. In general, allrelays 430 (R1-R5) between an AP 410 and a leaf STA 420 may need to beable to exit a low power state (awaken) quickly, in order to transmit(relay) data in small chunks.

Techniques presented herein may be considered part of a power savingsprotocol that achieves the above two goals, allowing devices to conservepower and operate with limited amount memory. According to certainaspects, various mechanisms already defined in certain standards (e.g.,802.11 ah), for use in direct communications between an AP and stations,may be modified and extended for use in relay systems.

In various systems, such as IEEE 802.11ah, there may be motivations toutilize relay devices 430 between access points (APs) 410 and stations420. For example, the use of relays may be desirable because, even withpotential increased downlink (DL) range with 900 MHz (or other “sub-1GHz) carrier, it may not be sufficient in applications with remotesensors or scenarios with obstructions in AP to STA path. On the uplink,a STA may have substantially lower transmit power than an AP, so the STAmay not be able to reach the AP.

Key Characteristics of such systems may include the use of a multi-hoprelay using a tree structure, as shown in FTC. 4. A relay-node may beformed by any suitable entity, such as a non-AP-STA (e.g., any stationthat lacks the ability to act-or is not currently acting-as an AP) thatconnects to a parent node or an AP-STA that allows association by childnodes. Node-to-node security may be ensured, for example, by theconfiguration of PSK between each pair of nodes. Relay nodes may support4-address format with backward learning bridge. In some cases, automaticconfiguration and reconfiguration may be achieved, for example, with arelay node able to attach to a better “parent node,” A relay node may,thus, monitor the health of the link to a parent node.

As will be described in greater detail below, a relay node may also beconfigured to enter a low power state (e.g., a sleep mode with radiocomponents powered down) in order to conserve battery power. In somecases, a relay node may be configured with scheduled wakeup periods,during which the relay node may transmit and receive data. To conservepower, however, rather than exit the low power state each wakeup period,a relay may decide to exit the low power state only when one or moreconditions are met (e.g., when there has been an indication there isdata for the relay node to transmit or receive).

In general, an AP and STA may perform similar (e.g., symmetric orcomplementary) operations. Therefore, for many of the techniquesdescribed herein, an AP or STA may perform similar operations. To thatend, the following description will sometimes refer to an “AP/STA” toreflect that an operation may be performed by either. Although, itshould be understood that even if only “AP” or “STA” is used, it doesnot mean a corresponding operation or mechanism is limited to that typeof device.

Traffic Indication Map

In systems where many stations stay in lower power states much of thetime, a traffic indication map (TIM) may be provided to indicate whichstations have traffic (and therefore should awake to receive thattraffic). A TIM information element (IE) is described in IEEE 802.11standards, using a bitmap to indicate to any sleeping listening stationsif an AP has any buffered frames for it. This TIM IE with thecorresponding bitmap is typically sent in on an AP's beacons, with eachbit in the bitmap corresponding to the Association Id (AID) of astation. In some cases, an AP may transmit a smaller TIM bitmap, forexample, if it expects that only a few number of stations will beasleep. In this case, only a subset of bitmap values may be conveyed inwhat is referred to as a partial virtual bitmap. Bitmap control andlength fields of the TIM information element are used to convey a rangeof AID values corresponding to the partial virtual bitmap.

In some cases, rather than provide a one-to-one mapping between bits andAIDs, a hierarchical approach may be used. For example, as illustratedin the diagram 500 of FIG. 5 the total AID space may be divided intosmall blocks in a hierarchical manner and only blocks with non-zerovalues may be transmitted. This approach allows a TIM for a relativelylarge AID space to be broken into small groups of STAs, which may beeasier to maintain. As illustrated, a three level hierarchy may includePages, blocks within a page, and sub-blocks within a block (e.g., witheach sub-block corresponding to 8 individual stations).

FIG. 6A illustrate an example 600A structure of a partial virtual bitmapfor such a hierarchical structure, in accordance with certain aspects ofthe present disclosure. As illustrated, the structure 600A may havevariable length encoded block subfields. As illustrated in FIG, 6B, eachencoded block subfield 600B may have a block control subfield, blockoffset subfield, and an encoded block information subfield. As shown inFIG. 6C, the block control subfield 600C may indicate what type ofencoding mode is used in the encoded block field, with example encodingtypes shown in table 600D of FIG. 6D. As illustrated, a single ADencoding mode may be used.

FIG. 7 illustrates an example structure 700 for encoded blockinformation subfield where the single AID encoding mode is used. Asillustrated, in single AID encoding mode, the encoded block informationsubfield may include a single AID subfield containing 6 bits (e.g., the6 least significant bits) of an AID indicated in the block and remainingbits may be reserved. The value of the single AID subfield along withother information included in the partial virtual bitmap indicates thatthere is unicast traffic buffered for a particular station which isidentified by its AID. The AID of the station may be obtained byconcatenating the Single AID subfield, the Block Offset field, and thePage Index field, in sequence from the least significant bit to the mostsignificant bit.

Traffic Indication Map

As noted above, encoding the partial virtual bitmap that is included inthe TIM element may help reduce overhead (relative to a “baselinemechanism” of transmitting a bitmap with bits for an entire AID space).However, due to the re-design that comes as a result of the encoding,the baseline mechanism may not readily allow for the indication oftraffic buffered at one or more BSSs while operating in a Multiple BSSIDmode.

Aspects of the present disclosure, however, may provide signalingmechanisms to enable a Multiple BSSID mode and other group-cast trafficdelivery mechanisms in systems (e.g., 802.11ah systems) by using anencoded Partial Virtual Bitmap field that may be defined for stationscapable of supporting such a mode (e.g., sub-1 GHz “S1G” STAs). As usedherein, the term group-cast generally refers to traffic addressed tomore than one recipient, such as multicast and broadcast traffic.Techniques presented herein may avoid having to re-use an AID space fromwhich AIDs are assigned to non-AP STAs in order to identify multipleBSSs. As described in greater detail below, techniques presented hereinmay identify these BSSs by using BSS AIDs that are included in EncodedBlocks that may be called Encoded BSS Blocks,

FIG. 8 illustrates example operations 800 for wireless communications byan apparatus, in accordance with aspects of the present disclosure. Theoperations 800 may be performed by an apparatus, such as a station,acting as an access point.

Operations 800 may begin at 802, by generating a frame with aninformation element (TE) having a partial virtual bitmap field thatindicates one or more basic service sets (BSSs) that have bufferedgroup-cast traffic, wherein the partial virtual bitmap field comprisesat least one encoded subfield that identifies at least one individualBSS having buffered group-cast traffic using an identifier of theindividual BSS (e.g., a BSS AID). At 804, the apparatus outputs theframe containing the IE for transmission.

FIG. 9 is a block diagram of operations 900 for wireless communicationsby an apparatus, in accordance with aspects of the present disclosure.The operations 900 may be performed by an apparatus, such as a TIMstation,

Operations 900 may begin at 902, by receiving a frame containing aninformation element (IE), wherein the IE comprises a partial virtualbitmap field that indicates zero or more basic service sets (BSSs) thathave buffered group-cast traffic and at least one encoded subfield thatidentifies at least one individual BSS having buffered group-casttraffic using an identifier of the individual BSS. At 904, determine thepresence of buffered group-cast traffic for the apparatus based on thepartial virtual bitrnap and to decide whether or not to change at leastone power state to receive the buffered group-cast traffic, based on thedetermination.

According to certain aspects, the encoded subfield may be an encodedblock field and may comprise a Single AID subfield and the TIM IEfurther comprises a page index field and block offset field that arecombinable with the AID subfield to generate the AID of the individualBSS (BSS AID) as described above. The encoded block field comprises anindication (e.g., via the BSS Indicator Bit shown in FIG. 10) of whetherthe identifier derived from the Single AID subfield indicates bufferedgroup-cast traffic for the individual BSS (i.e., a BSS AID) or thewhether it indicates unicast traffic for an individual station whose AIDmay be constructed using the Single AID subfield. In some cases,generation of the AID of the individual BSS (BSS AID) uses only a subsetof one or more bits of the page index field. In such cases, generationof the AID of the individual BSS uses default values, rather than thevalues of the certain unused bits of the page index field that isincluded in the TIM element that carries the partial virtual bitmapfield.

In some cases, the techniques may be used in systems supporting MultipleBSSID capability, with details of operation determined on a category ofstations in the system (e.g., with a first category including non-S1GSTAs and a second category including S1G STAs). In some cases, thepartial virtual bitmap field may be transmitted in a BSSID Beacon, S1GBeacon or DMG Beacon frame, may indicate the presence or absence oftraffic to be delivered to all stations associated to a transmitted ornon-transmitted BSSID. For the first category, the first category, thefirst 2^(n) bits of the bitmap in the Partial Virtual Bitmap field maybe reserved for the indication of group addressed frame for thetransmitted and all non-transmitted BSSIDs. For the second category, thefirst zero or more Encoded Blocks in the Partial Virtual Bitmap fieldmay be reserved for the indication of group addressed frame for thetransmitted and all non-transmitted BSSIDs. For the first category theAID space may be shared by all BSSs and the lowest AID value assigned toan associated STA may be 2^(n). For cases in the second category, thelowest AID assigned to an associated STA may be 1. In either case theEncoded Blocks that contain BSS AIDs may be the first blocks, precedingthe Partial Virtual Bitmap field. Note that in the cases of the firstcategory any encoding method can be applied to the partial virtualbitmap. In these cases the same principle of ignoring the page indexvalue for the purpose of obtaining the BSS AID is still valid.

In some cases, when Multiple BSSID capability is not enabled (e.g.,dot11MultiBSSIDActivated is false and dot11S1GoptionImplemented isfalse), the Partial Virtual Bitmap field consists of octets numbered N1to N2 of the traffic indication virtual bitmap, where N1 is the largesteven number such that bits numbered 1 to (N1×8)-1 in the trafficindication virtual bitmap may be all 0 and N2 may be the smallest numbersuch that bits numbered (N2+1)×8 to 2007 in the virtual bitmap are all0. In this case, the Bitmap Offset subfield value may contain the numberN1/2, and the Length field is set to (N2−N1)+4

In some cases, when Multiple BSSID capability is not enabled (e.g.,dot11MultiBSSIDActivated is true), the non-S1G Partial Virtual Bitmapfield of the TIM element may be constructed as follows, where themaximum possible number of BSSIDs is an integer power of 2, n=log2(maximum possible number of BSSIDs), k is the number of actuallysupported nontransmitted BSSIDs, and k<(2^(n)−1). In these cases, themaximum size of the non-S1G Partial Virtual Bitmap field of the TIMelement is 2^(n)−1.

For a non-S1G BSS, the bits 1 to k of the bitmap may be used to indicatethat one or more group addressed frames are buffered for each APcorresponding to a nontransmitted BSSID. The AIDS from 1 to k are notallocated to a non-S1G STA. In a non-S1G BSS, the AIDs from (k+1) to(2^(n)−1) may be reserved and set to 0. The remaining AIDs may be sharedby the non-S1G BSSs corresponding to the transmitted BSSID and allnontransmitted BSSIDs. In an S1G BSS, these bits, 1 to k, may beincluded in BSS Encoded Blocks and are identified as BSS AIDs. In thiscase, the BSS AIDs may not form part of the AID space from which AIDsare assigned to non-AP STAs. The AID space may be shared by the S1G BSSscorresponding to the transmitted BSSID and all nontransmitted BSSIDs.

When the DTIM Count field is 0 for a BSS that has a nontransmittedBSSID, and one or more group addressed frames are buffered at the AP forthis BSS, and the corresponding bits from bit 1 to bit k may be set to1.

Each bit starting from bit 2 ^(n) in the non-S1G traffic-indicationvirtual bitmap and starting from bit 1 in the S1G traffic-indicationvirtual bitmap may correspond to individually addressed traffic bufferedfor a specific STA within any BSS corresponding to a transmitted ornontransmitted BSSID at the time the Beacon frame is transmitted. Thecorrespondence may be based on the AID of the STA.

Based upon an AP's knowledge of the capability of associated stations tosupport the multiple BSSID capability, as indicated by the correspondingfield in the Extended Capabilities element and the content of thetraffic indication virtual bitmap, the AP may encode the Partial VirtualBitmap and the Bitmap Control field of the TIM element using one of thethree following methods, with the particular operations depending on thecategory of stations in the system.

For example, for a system with a first category of stations (e.g.,non-S1G), an AP may use one method (referred to as Method B describedbelow) when it determines that the bit for each associated non-AP STA inthe traffic indication virtual bitmap, when correctly set, can bereconstructed by each non-AP STA from the received TIM element,Otherwise, the AP may use a second method (referred to Method Adescribed below), while an AP in a system with a second category ofstations (e.g., S1G) may use a third method (referred to as Method Cdescribed below).

According to Method A, the Partial Virtual Bitmap field pray consist ofoctets numbered 0 to N2 of the traffic indication virtual bitmap, whereN2 is the smallest number such that bits numbered (N2+1)×8 to 2007 inthe traffic indication virtual bitmap(#234) are all 0. If such a valueN2 does not exist, that is, when not all bits in the last octet of thetraffic indication virtual bitmap are equal to 0, N2=250. When usingthis method, the Bitmap Offset subfield value may contains the number 0,and the Length field is N2+4.

According to Method B, the Partial Virtual Bitmap field may consist of aconcatenation of octets numbered 0 to N0−1 and octets numbered N1 to N2of the traffic indication virtual bitmap, where N0 is the smallestpositive integer such that N0×8−2n<8. If N0 is an odd number, then N1 isthe largest odd number such that N0<N1 and each of the bits N0×8 to(N1×8−1) is equal to 0, When N0 is an even number, N1 is the largesteven number such that N0<N1 and each of the bits N0×8 to (N1×8 1) isequal to 0. If such a value N1>N0 does not exist, N1=N0. Additionally,N2 is the smallest integer value for which the values for bit (N2+1)×8to 2007 in the traffic indication virtual bitmap(#234) are all 0. Ifsuch a value N2 does not exist, that is, when not all bits in the lastoctet of the traffic indication virtual bitmap are equal to 0, N2=250.When using this method, the Bitmap Offset subfield contains the value of(N1−N0)/2, and the Length field is N0+N2−N1+4.

According to aspects of the present disclosure, according to Method C,the Partial Virtual Bitmap field may consist of a concatenation ofEncoded Block subfields that contain BSS AIDs and Encoded Blocksubfields that contain AIDs.

For both Method A and Method B, when there are no frames buffered forany BSS corresponding to a transmitted or nontransmitted BSSIDsupported, the Partial Virtual Bitmap field may be encoded as a singleoctet equal to 0, the Bitmap Offset subfield is 0, and the Length fieldis 4. When there are no buffered individually addressed frames for anyBSS corresponding to a transmitted or nontransmitted BSSID, but thereare buffered group addressed frames for one or more of the BSSs, thenon-S1G Partial Virtual Bitmap field consists of the octets number 0 toN0−1 where N0 is the smallest positive integer such that (N0×8−2n<8),while the S1G Partial Virtual Bitmap field contains the one or moreEncoded Blocks that contain BSS AIDs. In this case, the Bitmap Offsetsubfield value may contain the number 0, and the Length field may beN0+3.

In some cases, in S1G scenarios (e.g., when dot11S1GOptionImplemented istrue), the Partial Virtual Bitmap field may be constructed with one ormore Encoded Block subfields if at least one bit in the trafficindication virtual bitmap that is encoded with that particular encodingmethod is equal to 1. In this case, the Encoded Block subfield mayconsist of the Block Control subfield, the Block Offset subfield, andthe Encoded Block Information subfield. When multiple BSSID is enabled(e.g., dot11MultipleBSSIDActivated is true), the Partial Virtual Bitmapfield contains zero or more BSS Encoded Block subfields. The EncodingMode subfield may indicates one of the four encoding modes: the BlockBitmap mode, the Single AID mode, the OLB (Offset, Length, Bitmap) mode,and the ADE (AID Differential Encode) mode. An Encoded Block is encodedwith Single AID mode and includes a BSS AID (i.e., the BSS Indicatorsubfield of its Encoded Block Information subfield is equal to 1). AnEncoded Block with Single AID mode that is not an Encoded BSS Block hasthe BSS Indicator subfield of its Subblock equal to 0. Other methods canbe used as well, as indicated above.

As illustrated in FIG. 10, the Encoded Block Information subfield 1000may consist of the Single AID subfield. As an example, the Single AIDsubfield may be 6 bits in length and contains the 6 LSBs of the singleAID in the Block. The BSS Indicator may be act to 1 if the Single AIDidentifies a BSS AID. Otherwise, it may be set to 0. The rest of thebits of the Encoded Block Information subfield may be reserved. If theBSS Indicator field is 0, the value in the Single AID subfield mayindicate traffic buffered for the STA whose AID is N, where N may beconstructed by concatenating the Single AID subfield/N[0:5]), the BlockOffset field (N[6:10]), and the Page Index field (N[11:12]) in sequencefrom LSB to MSB. If the BSS Indicator field is 1, the value in theSingle AID subfield indicates that one or more group addressed arebuffered at the AP for the BSS which BSS AID is N, where N may beconstructed as described above but with the value of the Page Indexfield (N[11:12]) equal to 0 (i.e., the BSS AID does not depend on thevalue of the Page Index field in the Bitmap Control field).

If the BSS Indicator field is 0, the value in the Single AID subfieldmay indicate traffic buffered for the STA whose AID is N, where N isconstructed by concatenating the Single AID subfield(N[0:5]), the BlockOffset field (N[6:10]), and the Page Index field (N[11:12]) in sequencefrom LSB to MSB. If the BSS Indicator field is 1, the value in theSingle AID subfield may indicate that one or more types of groupaddressed traffic is buffered at the AP for the BSS which BSS AID is N,where the value of the Page Index field (N[11:12]) may be assumed to bea default value (e.g., a default value of 0 may be assumed for either orboth of these bits regardless of the Page Index field value in theBitmap Control field of the TIM element).

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Generally,where there are operations illustrated in figures, those operations mayhave corresponding counterpart means-plus-function components withsimilar numbering, For example, operations 800 and 900 illustrated inFIGS. 8 and 9 correspond to means 800A and 900A illustrated in FIGS. 8Aand 9A, respectively.

For example, means for transmitting may comprise a transmitter (e.g.,the transmitter unit 222) and/or an antenna(s) 224 of the access point110 illustrated in FIG. 2 or the transmitter 310 and/or antenna(s) 316depicted in FIG. 3. Means for receiving may comprise a receiver (e.g.,the receiver unit 222) and/or an antenna(s) 224 of the access point 110illustrated in FIG. 2 or the receiver 312 and/or antenna(s) 316 depictedin FIG. 3. Means for processing, means for determining, means fordetecting, means for scanning, means for selecting, means forgenerating, or means for terminating operation may comprise a processingsystem, which may include one or more processors, such as the RX dataprocessor 242, the TX data processor 210, and/or the controller 230 ofthe access point 110 illustrated in FIG. 2 or the processor 304 and/orthe DSP 320 portrayed in FIG. 3.

According to certain aspects, such means may be implemented byprocessing systems configured to perform the corresponding functions byimplementing various algorithms (e.g., in hardware or by executingsoftware instructions) described above for performing fast association.For example, means for identifying wakeup periods may be implemented bya processing system performing an algorithm that identifies wakeupperiods based on a configuration (e.g., via an IE), means fordetermining whether to enable radio functions during wakeup periods maybe implemented by a (same or different) processing system performing analgorithm that takes, as input, the wakeup periods and whether thepresence of data has been indicated, while means for enabling radiofunctions may be implemented a (same or different) processing systemperforming an algorithm that takes, as input, the decision from meansfor determining and generates signals to enable/disable the radiofunctions accordingly.

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “determining” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” may include resolving, selecting, choosing, establishingand the like.

As used herein, the term receiver may refer to an RF receiver (e.g., ofan RF front end) or an interface (e.g., of a processor) for receivingstructures processed by an RF front end (e.g., via a bus). Similarly,the term transmitter may refer to an RF transmitter of an RF front endor an interface (e.g., of a processor) for outputting structures to anRF front end for transmission (e.g., via a bus).

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover: a, b, c,a-b, a-c, b-c, and a-b-c, as well as any combination with multiples ofthe same element (e.g., a-a, a-a-a, a-a-b, a-b-b, a-c-c, b-b, b-b-b,b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

The various illustrative logical blocks, modules and circuits describedin connection with the present disclosure may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device (PLD),discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any commercially available processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thepresent disclosure may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in any form of storage medium that is knownin the art. Some examples of storage media that may be used includerandom access memory (RAM), read only memory (ROM), flash memory. EPROMmemory, EEPROM memory, registers, a hard disk, a removable disk, aCD-ROM and so forth. A software module may comprise a singleinstruction. or many instructions, and may be distributed over severaldifferent code segments, among different programs, and across multiplestorage media. A storage medium may be coupled to a processor such thatthe processor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

The functions described may be implemented in hardware, software,firmware, or any combination thereof. If implemented in hardware, anexample hardware configuration may comprise a processing system in awireless node. The processing system may be implemented with a busarchitecture. The bus may include any number of interconnecting busesand bridges depending on the specific application of the processingsystem and the overall design constraints. The bus may link togethervarious circuits including a processor, machine-readable media, and abus interface. The bus interface may be used to connect a networkadapter, among other things, to the processing system via the bus. Thenetwork adapter may be used to implement the signal processing functionsof the PHY layer. In the case of a user terminal 120 (see FIG. 1), auser interface (e.g., keypad, display, mouse, joystick, etc.) may alsobe connected to the bus. The bus may also link various other circuitssuch as timing sources, peripherals, voltage regulators, powermanagement circuits, and the like, which are well known in the art, andtherefore, will not be described any further.

The processor may be responsible for managing the bus and generalprocessing, including the execution of software stored on themachine-readable media. The processor may be implemented with one ormore general-purpose and/or special-purpose processors. Examples includemicroprocessors, rnicrocontrollers, DSP processors, and other circuitrythat can execute software. Software shall be construed broadly to meaninstructions, data, or any combination thereof, whether referred to assoftware, firmware, middleware, microcode, hardware descriptionlanguage, or otherwise. Machine-readable media may include, by way ofexample, RAM (Random Access Memory), flash memory, ROM (Read OnlyMemory), PROM (Programmable Read-Only Memory), EPROM (ErasableProgrammable Read-Only Memory), EEPROM (Electrically ErasableProgrammable Read-Only Memory), registers, magnetic disks, opticaldisks, hard drives, or any other suitable storage medium, or anycombination thereof. The machine-readable media may be embodied in acomputer-program product. The computer-program product may comprisepackaging materials.

In a hardware implementation, the machine-readable media may be part ofthe processing system separate from the processor. However, as thoseskilled in the art will readily appreciate, the machine-readable media,or any portion thereof, may be external to the processing system. By wayof example, the machine-readable media may include a transmission line,a carrier wave modulated by data and/or a computer product separate fromthe wireless node, all which may be accessed by the processor throughthe bus interface. Alternatively, or in addition, the machine-readablemedia, or any portion thereof, may be integrated into the processor,such as the case may be with cache and/or general register files.

The processing system may be configured as a general-purpose processingsystem with one or more microprocessors providing the processorfunctionality and external memory providing at least a portion of themachine-readable media, all linked together with other supportingcircuitry through an external bus architecture. Alternatively, theprocessing system may be implemented with an ASIC (Application SpecificIntegrated Circuit) with the processor, the bus interface, the userinterface in the case of an access terminal), supporting circuitry, andat least a portion of the machine-readable media integrated into asingle chip, or with one or more FPGAs (Field Programmable Gate Arrays),PLDs (Programmable Logic Devices), controllers, state machines, gatedlogic, discrete hardware components, or any other suitable circuitry, orany combination of circuits that can perform the various functionalitydescribed throughout this disclosure. Those skilled in the art willrecognize how best to implement the described functionality for theprocessing system depending on the particular application and theoverall design constraints imposed on the overall system.

The machine-readable media may comprise a number of software modules.The software modules include instructions that, when executed by theprocessor, cause the processing system to perform various functions. Thesoftware modules may include a transmission module and a receivingmodule. Each software module may reside in a single storage device or bedistributed across multiple storage devices. By way of example, asoftware module may be loaded into RAM from a hard drive when atriggering event occurs. During execution of the software module, theprocessor may load some of the instructions into cache to increaseaccess speed. One or more cache lines may then be loaded into a generalregister file for execution by the processor. When referring to thefunctionality of a software module below, it will be understood thatsuch functionality is implemented by the processor when executinginstructions from that software module.

If implemented in software, the functions may be stored or transmittedover as one or more instructions or code on a computer-readable medium.Computer-readable media include both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. A storage medium may be anyavailable medium that can be accessed by a computer. By way of example,and not limitation, such computer-readable media can comprise RAM, ROM,EEPROM, CD-ROM or other optical disk storage, magnetic disk storage orother magnetic storage devices, or any other medium that can be used tocarry or store desired program code in the form of instructions or datastructures and that can be accessed by a computer. Also, any connectionis properly termed a computer-readable medium. For example, if thesoftware is transmitted from a website, server, or other remote sourceusing a coaxial cable, fiber optic cable, twisted pair, digitalsubscriber line (DSL), or wireless technologies such as infrared (IR),radio, and microwave, then the coaxial cable, fiber optic cable, twistedpair, DSL, or wireless technologies such as infrared, radio, andmicrowave are included in the definition of medium. Disk and disc, asused herein, include compact disc (CD), laser disc, optical disc,digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Thus, in some aspects computer-readable media maycomprise non-transitory computer-readable media (e.g., tangible media).In addition, for other aspects computer-readable media may comprisetransitory computer-readable media (e.g., a signal). Combinations of theabove should also be included within the scope of computer-readablemedia.

Thus, certain aspects may comprise a computer program product forperforming the operations presented herein. For example, such a computerprogram product may comprise a computer-readable medium havinginstructions stored (and/or encoded) thereon, the instructions beingexecutable by one or more processors to perform the operations describedherein. For certain aspects, the computer program product may includepackaging material.

Further, it should be appreciated that modules and/or other appropriatemeans for performing the methods and techniques described herein can bedownloaded and/or otherwise obtained by a user terminal and/or basestation as applicable. For example, such a device can be coupled to aserver to facilitate the transfer of means for performing the methodsdescribed herein. Alternatively, various methods described herein can beprovided via storage means (e.g., RAM, ROM, a physical storage mediumsuch as a compact disc (CD) or floppy disk, etc.), such that a userterminal and/or base station can obtain the various methods uponcoupling or providing the storage means to the device. Moreover, anyother suitable technique for providing the methods and techniquesdescribed herein to a device can be utilized.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the methods and apparatus described above without departingfrom the scope of the claims.

What is claimed is:
 1. An apparatus for wireless communications,comprising: a processing system configured to generate a frame with aninformation element (IE) having a partial virtual bitmap field thatindicates zero or more basic service sets (BSSs) that have bufferedgroup-cast traffic, wherein the partial virtual bitmap field comprisesat least one encoded subfield that identifies at least one individualBSS having buffered group-cast traffic using one or more bits of anidentifier of the individual BSS; and an interface for outputting theframe containing the IE for transmission.
 2. The apparatus of claim 1wherein the identifier of the individual BSS comprises an associationidentifier or an assigned identifier (AID).
 3. The apparatus of claim 1,wherein the processing system is further configured to assume one ormore most significant bits of the identifier of the individual BSShaving at least one default value rather than an actual value of one ormore bits of a page index field included in the IE.
 4. The apparatus ofclaim 1, wherein the processing system is further configured to assume adefault value of 0 for at least two most significant bits of theidentifier of the individual BSS rather than an actual value of the pageindex field included in the IE.
 5. The apparatus of claim 1, wherein:the encoded subfield comprises a single association identifier subfieldor an assigned identifier (AID) subfield; and the IE further comprises apage index field and a block offset field, wherein the page index fieldand the block offset field can be used with the single associationidentifier subfield or the single AID subfield to generate an AID of theindividual BSS.
 6. The apparatus of claim 5, wherein the encodedsubfield comprises an indication of whether: an AID value associatedwith the single association identifier subfield or single AID subfieldindicates buffered group-cast traffic for the individual BSS; or an AIDvalue associated with the single association identifier subfield orsingle AID subfield indicates unicast traffic for a device.
 7. Theapparatus of claim 1, wherein the at least one encoded subfield precedesan association identifier or an assigned identifier of a device.
 8. Anapparatus for wireless communications, comprising: an interface forreceiving a frame containing an information element (IE), wherein the IEcomprises a partial virtual bitmap field that indicates zero or morebasic service sets (BSSs) that have buffered group-cast traffic and atleast one encoded subfield that identifies at least one individual BSShaving buffered group-cast traffic using one or more bits of anidentifier of the individual BSS; and a processing system configured todetermine the presence of buffered group-cast traffic for the apparatusbased on the partial virtual bitrnap and to decide whether or not tochange at least one power state to receive the buffered group-casttraffic, based on the determination.
 9. The apparatus of claim 8 whereinthe identifier of the individual BSS comprises an association identifieror an assigned identifier (AID).
 10. The apparatus of claim 8, wherein:the processing system is further configured to locally generate theidentifier of the individual BSS using less than all bits of a pageindex field included in the IE, wherein the determination is based onthe locally generated identifier.
 11. The apparatus of claim 8, whereinthe processing system is further configured to assume one or more mostsignificant bits of the identifier of the individual BSS having at leastone default value rather than an actual value of one or more bits of apage index field included in the IE.
 12. The apparatus of claim 8,wherein: the encoded subfield comprises a single association identifiersubfield or an assigned identifier (AID) subfield; the IE furthercomprises a page index field and a block offset field, wherein the pageindex field and the block offset field can be used with the singleassociation identifier subfield or single AID subfield; and theprocessing system is configured to locally generate an AID of theindividual BSS based on at least one of the single associationidentifier subfield or single AID subfield, page index field, or blockoffset field.
 13. The apparatus of claim 12, wherein the encodedsubfield comprises an indication of whether: an AID value associatedwith the single association identifier subfield or single AID subfieldindicates buffered group-cast traffic for the individual BSS; or an AIDvalue associated with the single association identifier subfield orsingle AID subfield indicates unicast traffic for a device; and theprocessing system is configured to locally generate the AID of theindividual BSS using at least one default value, rather than an actualvalue, of one or more bits of a page index field included in the IEbased on the indication.
 14. The apparatus of claim 8, wherein theprocessing system is further configured to assume at least one defaultvalue, rather than an actual value, of one or more bits of a page indexfield included in the IE, and locally generate an association identifieror an assigned identifier (AID) of the individual BSS based on theassumption.
 15. A method for wireless communications by an apparatus,comprising: generating, at an apparatus, a frame with an informationelement (IE) having a partial virtual bitmap field that indicates zeroor more basic service sets (BSSs) that have buffered group-cast traffic,wherein the partial virtual bitmap field comprises at least one encodedsubfield that identifies at least one individual BSS having bufferedgroup-cast traffic using one or more bits of an identifier of theindividual BSS; and outputting the frame containing the IE fortransmission.
 16. The method of claim 15, wherein the identifier of theindividual BSS comprises an association identifier or an assignedidentifier (AID).
 17. The method of claim 15, wherein the generatingcomprises assuming one or more most significant bits of the identifierof the individual BSS have at least one default value rather than anactual value of one or more bits of a page index field included in theIE.
 18. The method of claim 15, wherein the generating comprisesassuming a default value of 0 for at least two most significant bits ofthe identifier of the individual BSS rather than an actual value of thepage index field included in the IE.
 19. The method of claim 15,wherein: the encoded subfield comprises a single association identifiersubfield or an assigned identifier (AID) subfield; and the IE furthercomprises a page index field and a block offset field, wherein the pageindex field and the block offset field can be used with the singleassociation identifier subfield or single AID subfield to generate anAID of the individual BSS.
 20. The method of claim 19, wherein theencoded subfield comprises an indication of whether: an AID valueassociated with c single association identifier subfield or single AIDsubfield indicates buffered group-cast traffic for the individual BSS;or an AID value associated with the single association identifiersubfield single AID subfield indicates unicast traffic for a device. 21.The method of claim 15, wherein the at least one encoded subfieldprecedes, an association identifier or an assigned identifier of adevice.
 22. A method for wireless communications, comprising: receiving,at an apparatus, a frame containing an information element (IE), whereinthe IE comprises a partial virtual bitmap field that indicates zero ormore basic service sets (BSSs) that have buffered group-cast traffic andat least one encoded subfield that identities at least one individualBSS having buffered group-cast traffic using one or more bits of anidentifier of the individual BSS; and determining the presence ofbuffered group-cast traffic for the apparatus based on the partialvirtual bitmap and to decide whether or not to change at least one powerstate to receive the buffered group-cast traffic, based on thedetermination.
 23. The method of claim 22, wherein the identifier of theindividual BSS comprises an association identifier or an assignedidentifier (AID).
 24. The method of claim 22, the determining compriseslocally generating the identifier of the individual BSS using less thanall bits of a page index field included in the IE, wherein thedetermination is based on the locally generated identifier.
 25. Themethod of claim 22, wherein the determining comprises assuming one ormore most significant bits of the identifier of the individual BSS haveat least one default value rather than an actual value of one or morebits of a page index field included in the IE.
 26. The method of claim22, wherein: the encoded subfield comprises a single associationidentifier subfield or an assigned identifier (AID) subfield; the IEfurther comprises a page index field and a block offset field, whereinthe page index field and the block offset field can be used with thesingle association identifier subfield or single AID subfield togenerate an AID of the individual BSS and locally generating an AID ofthe individual BSS based on at least one of the single associationidentifier subfield, the single AID subfield, page index field, or blockoffset field.
 27. The method of claim 26, wherein the encoded subfieldcomprises an indication of whether: an AID value associated with thesingle association identifier subfield or the single AID subfieldindicates buffered group-cast traffic for the individual BSS, or an AIDvalue associated with the single association identifier subfield or thesingle AID subfield indicates unicast traffic for a device; and locallygenerating the AID of the individual BSS using at least one defaultvalue, rather than an actual value, of one or more bits of a page indexfield included in the IE, based on the indication.
 28. The method ofclaim 22, wherein the determining comprises assuming at least onedefault value, rather than an actual value, of one or more bits of apage index field included in the IE, and locally generate an associationidentifier or an assigned identifier (AID) of the individual BSS basedon the assumption.
 29. An apparatus for wireless communications,comprising: means for generating a frame with an information element(IE) having a partial virtual bitmap field that indicates zero or morebasic service sets (BSSs) that have buffered group-cast traffic, whereinthe partial virtual bitmap field comprises at least one encoded subfieldthat identifies at least one individual BSS having buffered group-casttraffic using one or more bits of an identifier of the individual BSS;and means for outputting the frame containing the IE for transmission.30. The apparatus of claim 29 wherein the identifier of the individualBSS comprises an association identifier or an assigned identifier (AID).31. The apparatus of claim 29, wherein the generating comprises assumingone or more most significant bits of the identifier of the individualBSS have at least one default value rather than an actual value of oneor more bits of a page index field included in the IE.
 32. The apparatusof claim 29, wherein the generating comprises assuming a default valueof 0 for at least two most significant bits of the individual BSS ratherthan an actual value of the page index field included in the IE.
 33. Theapparatus of claim 29, wherein: the encoded subfield comprises a singleassociation identifier subfield or an assigned identifier (AID)subfield; and the IE further comprises a page index field and a blockoffset field, wherein the page index field and the block offset fieldcan be used with the single association identifier subfield or thesingle AID subfield to generate the AID of the individual BSS.
 34. Theapparatus of claim 33, wherein the encoded subfield comprises anindication of whether: an AID value associated with the singleassociation identifier subfield or the single AID subfield indicatesbuffered group-cast traffic for the individual BSS; or an AID valueassociated with the single association identifier subfield or the singleAID subfield indicates unicast traffic for a device.
 35. The apparatusof claim 29, wherein the at least one encoded subfield precedes anassociation identifier or an assigned identifier of a device.
 36. Anapparatus for wireless communications, comprising: means for receiving aframe containing an information element (IE) wherein the IE comprises apartial virtual bitmap field that indicates zero or more basic servicesets (BSSs) that have buffered group-cast traffic and at least oneencoded subfield that identifies at least one individual BSS havingbuffered group-cast traffic using one or more bits of an identifier ofthe individual BSS; and means for determining the presence of bufferedgroup-cast traffic for the apparatus based on the partial virtual bitmapand to decide whether or not to change at least one power state toreceive the buffered group-cast traffic, based on the determination. 37.The apparatus of claim 36, wherein the identifier of the individual BSScomprises an association identifier or an assigned identifier (AID). 38.The apparatus of claim 36, wherein the means for determining locallygenerates the identifier of the individual BSS using less than all bitsof a page index field included in the IE, wherein the determination isbased on the locally generated identifier.
 39. The apparatus of claim38, wherein the means for determining assumes one or more mostsignificant bits of the identifier of the individual BSS have at leastone default value rather than an actual value of one or more bits of apage index field included in the IE.
 40. The apparatus of claim 36,wherein: the encoded subfield comprises a single association identifiersubfield or an assigned identifier (AID) subfield; and the IE furthercomprises a page index field and a block offset field, wherein the pageindex field and the block offset field can be used with the singleassociation identifier subfield or the single AID subfield; and locallygenerating an AID of the individual BSS based on at least one of thesingle association identifier subfield, the single AID subfield, pageindex field, or block offset field.
 41. The apparatus of claim 40,wherein the encoded subfield comprises an indication of whether: an AIDvalue associated with the single association identifier subfield, singleAID subfield indicates buffered group-cast traffic for the individualBSS; or an AID value associated with the single association identifiersubfield, single AID subfield indicates unicast traffic for a device;and locally generating the AID of the individual BSS using at least onedefault value, rather than an actual value, of one or more bits of apage index field included in the IE based on the indication.
 42. Theapparatus of claim 36, wherein the means for determining assumes atleast one default value, rather than an actual value, of one or morebits of a page index field included in the IE, and locally generate anassociation identifier or an assigned identifier (AID) of the individualBSS based on the assumption.
 43. A computer program product for wirelesscommunications by an apparatus comprising a computer-readable mediumhaving instructions for: generating a frame with a information element(IE) having a partial virtual bitmap field that indicates zero or morebasic service sets (BSSs) that have buffered group-cast traffic, whereinthe partial virtual bitmap field comprises at least one encoded subfieldthat identifies at least one individual BSS having buffered group-casttraffic using one or more bits of an identifier of the individual BSS;and outputting the frame containing the IE for transmission.
 44. Acomputer program product for wireless communications by an apparatuscomprising a computer-readable medium having instructions executable to:receiving, at an apparatus, a frame containing an information element(IE), wherein the IE comprises a partial virtual bitmap field thatindicates zero or more basic service sets (BSSs) that have bufferedgroup-cast traffic and at least one encoded subfield that identifies atleast one individual BSS having buffered group-cast traffic using one ormore bits of an identifier of the individual BSS; and determining thepresence of buffered group-cast traffic for the apparatus based on thepartial virtual bitmap and to decide whether or not to change at leastone power state to receive the buffered group-cast traffic, based on thedetermination.
 45. An access point, comprising: at least one antenna; aprocessing system configured to generate a frame with an informationelement (IE) having a partial virtual bitmap field that indicates zeroor more basic service sets (BSSs) that have buffered group-cast traffic,wherein the partial virtual bitmap field comprises at least one encodedsubfield that identifies at least one individual BSS having bufferedgroup-cast traffic using one or more bits of an identifier of theindividual BSS; and a transmitter configured to transmit, via the atleast one antenna, the frame containing the IE for transmission.
 46. Awireless station, comprising: at least one antenna; a receiverconfigured to receive, via the at least one antenna, a frame containingan information element (IE), wherein the IE comprises a partial virtualbitmap field that indicates zero or more basic service sets (BSSs) thathave buffered group-cast traffic and at least one encoded subfield thatidentifies at least one individual BSS having buffered group-casttraffic using one or more bits of an identifier of the individual BSS;and a processing system configured to determine the presence of bufferedgroup-cast traffic for the apparatus based on the partial virtual bitmapand to decide whether or not to change at least one power state toreceive the buffered group-cast traffic, based on the determination.